Multimodal polyethylene composition

ABSTRACT

A bimodal polyethylene composition, products made therefrom, methods of making and using same, and articles, including bottle caps and closures, containing same.

FIELD

The field includes polyethylene compositions, products made therefrom,methods of making and using same, and articles containing same.

INTRODUCTION

Patent application publications in the Field include CA 2427685 A1; EP3058002A1; US 2004/0266966 A1; US 2005/0054790 A1; US 2007/0007680 A1;US 2010/0084363 A1; US 2014/0242314 A1; US 2015/0017365 A1; US2015/0274947 A1; WO 2003/016396 A1; WO 2004/101674 A1; WO 2006/045738A1; WO 2010/000557 A2; WO 2015/055392 A1; and WO 2015/069637 A2. Patentsin the Field include EP 2285843 B1; U.S. Pat. Nos. 7,250,473 B2;7,576,166 B2; 7,897,710 B2; 8,008,403 B2; 8,476,370 B2; 8,627,840 B2;8,846,188 B2; 8,957,158 B2; 9,017,784 B2; 9,090,762 B2; 9,249,286 B2;9,284,389 B2; and 9,309,338 B2.

Polyethylene polymers have numerous commercial applications. Theseinclude films, sheets, injection molded articles, and extruded articles.The films and sheets are used in packaging applications andnon-packaging applications. Examples are agricultural film, foodpackaging, garment bags, grocery bags, heavy-duty sacks, industrialsheeting, pallet and shrink wraps, and bags. The injection moldedarticles include buckets, freezer containers, lids, and toys. Theextruded articles include pipes and coating layers of electrical cables.

US 2004/0266966 A1 relates to a multimodal polyolefin pipe. WO2004/101674 A1 relates to a polymer composition and process tomanufacture high molecular weight-high density polyethylene and filmtherefrom. US 2010/0084363 A1 relates to high-density polyethylenecompositions, method of making the same, injection molded articles madetherefrom, and method of making such articles, which include a wirecable jacketing, a conduit pipe, an injection blow molded bottle, and abottle cap closure.

SUMMARY

We provide a bimodal polyethylene composition (“inventive bimodal PEcomposition”) made with a bimodal catalyst system, products madetherefrom, methods of making and using same, and articles containingsame. The inventive bimodal polyethylene composition has properties thatenable it to be used to make a bottle cap or closure.

The inventive bimodal PE composition also may be used in otherapplications.

DRAWINGS

FIG. 1 contains drawings of structural formulas of (pro)catalysts.

FIG. 2 is a GPC chromatogram of inventive examples 1 and 2 of theinventive bimodal PE composition and a comparative composition.

DETAILED DESCRIPTION

The Summary and Abstract are incorporated here by reference.

Certain inventive embodiments are described below as numbered aspectsfor easy cross-referencing. Additional embodiments are describedelsewhere herein.

Aspect 1. A bimodal polyethylene composition comprising a lowermolecular weight (LMW) polyethylene component and a higher molecularweight (HMW) polyethylene component, wherein each of the LMW and HMWpolyethylene components comprises ethylene-derived monomeric units and(C₃-C₂₀)alpha-olefin-derived comonomeric units; and wherein the bimodalpolyethylene composition is characterized by each of limitations (a) to(e): (a) a resolved bimodality (resolved molecular weight distribution)showing in a chromatogram of gel permeation chromatography (GPC) of thebimodal polyethylene composition, wherein the chromatogram shows a peakrepresenting the HMW polyethylene component, a peak representing the LMWpolyethylene component, and a local minimum in a range of Log(molecularweight) (“Log(MW)”) 3.5 to 5.5, alternatively 4.0 to 5.2, alternatively4.6 to 4.9 between the Log(MW) peak representing the HMW polyethylenecomponent and the Log(MW) peak representing the LMW polyethylenecomponent, measured according to Bimodality Test Method, describedlater; (b) a density from 0.950 to 0.960 g/cm³, alternatively 0.951 to0.959 g/cm³, alternatively 0.952 to 0.958 g/cm³, alternatively 0.954 to0.956 g/cm³, measured according to ASTM D792-13 Method B; (c) a meltindex (I₂) of from 0.5 to 1.5 g/10 min., alternatively 0.50 to 1.20 g/10min., alternatively 0.51 to 1.10 g/10 min. measured according to ASTMD1238-13 (190° C., 2.16 kg); (d) a melt flow ratio (I₂₁/I₂) of from 150to 300, alternatively from 175 to 295, alternatively from 195 to 285,alternatively from 220 to 279 wherein I₂ is measured as above and I₂₁ isflow index measured according to ASTM D1238-13 (190° C., 21.6 kg); (e) aflow index (I₅) from 2.0 to 10.0 g/10 min., alternatively from 2.5 to8.0 g/10 min., alternatively from 2.8 to 7.5 g/10 min. measuredaccording to ASTM D1238-13 (190° C., 5.0 kg); and wherein the HMWpolyethylene component of the bimodal polyethylene composition ischaracterized by limitations (f) and (g): (f) a weight-average molecularweight (Mw) of greater than 350,000 grams per mole (g/mol),alternatively from 400,000 to 550,000 g/mol, alternatively from 470,000to 520,000 g/mol as measured by Gel Permeation Chromatography Method(described later); and (g) a molecular mass dispersity, Ð_(M), (Mw/Mn)greater than 3.50, alternatively from 3.80 to 4.50, alternatively from3.90 to 4.10.

Aspect 2. The bimodal PE composition of aspect 1 further described byany one of limitations (i) to (vi): (i) a spiral flow length of from 25to 40 centimeters (cm) measured at 68.95 megapascals (MPa), a spiralflow length from 30 to 60 cm measured at 103.4 MPa, and/or a spiral flowlength from 40 to 70 cm measured at 137.9 MPa according to the SpiralFlow Length Test Method, described later; (ii) an environmental stresscrack resistance (ESCR) F50 measured according to ASTM D1693-15 in 10weight percent (wt %) Igepal CO-630 in water at 50° C. of greater than500 hours, alternatively greater than 700 hours, alternatively greaterthan 1,000 hours, and in some aspects at most 10,000 hours; (iii) ashrinkage from melt to solid form of from 3.0% to 5.0%, alternatively3.0% to 4.5% in flow direction and/or a shrinkage from melt to solidform of from 0.2% to 1.5% in cross-flow direction, measured according toASTM D-955 utilizing a 60 mm×60 mm×2 mm plaques; (iv) an oxidativeinduction time (OIT) of greater than 40 minutes, alternatively greaterthan 50 minutes, alternatively greater than 60 minutes, alternativelyfrom 60.0 to 70 minutes at 210° C. as measured by differential scanningcalorimetry (DSC) according to OIT Test Method described later; (v) atleast two of (i) to (iv); (vi) each of (i) to (iv).

Aspect 3. The bimodal PE composition of aspect 1 further described byany one of limitations (i) to (vii): (i) a molecular mass dispersity(M_(w)/M_(n)), Ð_(M) (pronounced D-stroke M), from 15 to 30,alternatively from 17 to 25, alternatively from 19 to 22, measuredaccording to Gel Permeation Chromatography (GPC) Test Method, describedlater; (ii) a weight average molecular weight (M_(n)) of the LMWpolyethylene component from 4,000 to 6,000 g/mol, alternatively from4,800 to 5,400 g/mol, alternatively from 5,001 to 5,199 g/mol and aM_(n) of the HMW polyethylene component from 110,000 to 130,000 g/molalternatively from 116,000 to 126,000 g/mol, alternatively from 120,001to 122,500 g/mol, measured according to GPC Test Method, describedlater, after deconvoluting the LMW and HMW polyethylene components ofthe bimodal PE composition according to Deconvoluting Test Method,described later; (iii) no measurable, alternatively no detectable,amount of long chain branching per 1,000 carbon atoms (“LCB Index”),measured according to LCB Test Method (described later); (iv) both (i)and (ii); (v) both (i) and (iii); (vi) both (ii) and (iii); and (vii)each of (i) to (iii).

Aspect 4. The bimodal PE composition of any one of aspects 1 to 3further described by any one of limitations (i) to (iv): (i) the(C₃-C₂₀)alpha-olefin-derived comonomeric units are derived from1-butene; (ii) the (C₃-C₂₀)alpha-olefin-derived comonomeric units arederived from 1-hexene; (iii) the (C₃-C₂₀)alpha-olefin-derivedcomonomeric units are derived from 1-octene; and (iv) the(C₃-C₂₀)alpha-olefin-derived comonomeric units are derived from acombination of any two, alternatively each of 1-butene, 1-hexene, and1-octene.

Aspect 5. A bimodal polyethylene composition made by copolymerizingethylene (monomer) and at least one (C₃-C₂₀)alpha-olefin (comonomer)with a mixture of a bimodal catalyst system and a trim solution in thepresence of molecular hydrogen gas (H₂) and, optionally, an inducedcondensing agent (ICA) in one, two or more polymerization reactors(e.g., one fluidized bed gas phase reactor) under (co)polymerizingconditions; wherein prior to being mixed together the trim solutionconsists essentially of a(tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconium complex(procatalyst, e.g.,(tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconium dimethyl) and an inert liquid solvent (e.g., liquid alkane) and the bimodalcatalyst system consists essentially of an activator species(derivative, e.g., a methylaluminoxane species), abis(2-pentamethylphenylamido)ethyl)amine zirconium complex and a(tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconiumcomplex, all disposed on a solid support (e.g., a hydrophobic fumedsilica); and wherein the (co)polymerizing conditions comprise a reactiontemperature from 80 degrees (°) to 110° Celsius (C.), alternatively 83°to 106° C., alternatively 83° to 87° C., alternatively 91° to 100° C.,alternatively 101° to 106° C.; a molar ratio of the molecular hydrogengas to the ethylene (H2/C2 molar ratio) from 0.001 to 0.020,alternatively 0.002 to 0.015, alternatively 0.005 to 0.010; and a molarratio of the comonomer (Comer) to the ethylene (Comer/C2 molar ratio)from 0.005 to 0.050, alternatively 0.008 to 0.030, alternatively 0.015to 0.025. The bimodal PE composition may be that of any one of aspects 1to 4.

Aspect 6. A method of making a bimodal polyethylene composition, themethod comprising contacting ethylene (monomer) and at least one(C₃-C₂₀)alpha-olefin (comonomer) with a mixture of a bimodal catalystsystem and a trim solution in the presence of molecular hydrogen gas(H₂) and, optionally, an induced condensing agent (ICA) in one, two ormore polymerization reactors under (co)polymerizing conditions, therebymaking the bimodal polyethylene composition; wherein prior to beingmixed together the trim solution consists essentially of a(tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconium complex(procatalyst, e.g.,(tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconiumdimethyl) and an inert liquid solvent (e.g., liquid alkane) and thebimodal catalyst system consists essentially of an activator species(derivative, e.g., a methylaluminoxane species), a non-metalloceneligand-Group 4 metal complex (e.g.,bis(2-pentamethylphenylamido)ethyl)amine zirconium complex) and ametallocene ligand-Group 4 metal complex (e.g.,(tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconiumcomplex), all disposed on a solid support (e.g., a hydrophobic fumedsilica); and wherein the (co)polymerizing conditions comprise a reactiontemperature from 80° to 110° C., alternatively 83° to 106° C.,alternatively 83° to 87° C., alternatively 91° to 100° C., alternatively101° to 106° C.; a molar ratio of the molecular hydrogen gas to theethylene (H2/C2 molar ratio) from 0.001 to 0.050, alternatively 0.001 to0.030, alternatively 0.002 to 0.025, alternatively 0.010 to 0.020; and amolar ratio of the comonomer (Comer) to the ethylene (Comer/C2 molarratio) from 0.005 to 0.10, alternatively 0.008 to 0.050, alternatively0.010 to 0.040 alternatively 0.008 to 0.030, alternatively 0.015 to0.025. The bimodal PE composition may be that of any one of aspects 1 to5. Alternatively in aspect 5 or 6, the bimodal catalyst system may beprepared, and then fed into the polymerization reactor(s) as asuspension (e.g., slurry) in a mineral oil and the trim solution may beprepared, and then fed into the polymerization reactor(s) as a solution,e.g., in a liquid alkane.

Aspect 7. The bimodal polyethylene composition of aspect 5 or the methodof aspect 6 may be further described by any one of limitations (i) to(vi): (i) wherein the bimodal catalyst system consists essentially of abis(2-pentamethylphenylamido)ethyl)amine zirconium complex and a(tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconium complexin a molar ratio thereof from 1.0:1.0 to 5.0:1.0, respectively,alternatively 1.5:1.0 to 2.5:1.0, alternatively 2.0:1.0 to 4.0:1.0,2.5:1.0 to 3.49:1.0, alternatively from 2.7:1.0 to 3.3:1.0,alternatively from 2.9:1.0 to 3.1:1.0, alternatively 1.5:1.0,alternatively 2.0:1.0, and a methylaluminoxane species, all disposed byspray-drying onto the solid support; (ii) wherein the bimodal catalystsystem further consists essentially of mineral oil and the solid supportis a hydrophobic fumed silica (e.g., a fumed silica treated withdimethyldichlorosilane); (iii) wherein the mixture is a suspension ofthe bimodal catalyst system in mineral oil and the trim solution andwherein the mixture is premade and then fed into the polymerizationreactor(s); (iv) wherein the trim solution is made by dissolving(tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconiumdimethyl in the inert liquid solvent (e.g., liquid alkane) to give thetrim solution; (v) wherein the polymerization reactor(s) is onefluidized bed gas phase reactor and the method is a gas phasepolymerization; and (vi) each of (i) to (v). The molar ratio of thebis(2-pentamethylphenylamido)ethyl)amine zirconium complex to the(tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconium complexmay be based on molar ratio of their respective Zr atom contents, whichmay be calculated from ingredient weights (e.g., weights ofbis(2-pentamethylphenylamido)ethyl)amine zirconium dibenzyl and(tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconiumdichloride) or may be analytically measured.

Aspect 8. A manufactured article comprising a shaped form of the bimodalpolyethylene composition of any one of aspects 1 to 5.

Aspect 9. The manufactured article of aspect 8 selected from: coatings,films, sheets, extruded articles, and injection molded articles. Themanufactured article may be a coating layer (e.g., of a coated article),pipe, film (e.g., blown film), agricultural film, food packaging,garment bags, grocery bags, heavy-duty sacks, industrial sheeting,pallet and shrink wraps, bags, buckets, freezer containers, lids, andtoys.

Aspect 10 A bottle cap or closure comprising a base member and a skirtmember, the base member defining a perimeter edge therearound, and theskirt member being in operative connection to the perimeter edge of thebase member and extending axially from the perimeter of the base member;wherein the skirt member defines an inner surface; wherein the basemember being for sealing a bottle opening of a bottle and the skirtmember being for operatively attaching the bottle cap or closure to anexterior cap-or-closure-receiving portion of the bottle proximate thebottle opening, wherein at least one of the base member and skirt memberof the bottle cap or closure is composed of the bimodal polyethylenecomposition of any one of aspects 1 to 5. The bottle cap or closure ismovable from a closed position to an open position when attached to thebottle, and may be movable from the open position to the closedposition. The inner surface of the skirt member of the bottle cap orclosure forms a seal against the exterior cap-or-closure-receivingportion of the bottle so as to contain the contents of the bottletherein when the bottle cap or closure is affixed to the bottle and in aclosed position on the bottle. In some aspects the base member is freeof an aperture therein, alternatively the base member defines anaperture therein, wherein the aperture may be closed or open. In someaspects the inner surface of the skirt member defines a screw-threadedportion of the skirt member, wherein the screw-threaded portion isconfigured to screw onto a complementary screw-threaded exteriorcap-or-closure-receiving portion of the bottle. In some aspects theinner surface of the skirt member is not screw-threaded but defines alatching portion for snap-fitting onto a complementary designed exteriorcap-or-closure-receiving portion of the bottle. In some aspects thebottle cap or closure further comprises the bottle. The bottle may be aplastic carbonated beverage bottle and the bottle cap or closure may bea bottle cap. The bottle cap may be a condiment bottle, and the bottlecap or closure may be a closure for sealing the condiment bottle. Insome aspects the bottle cap or closure further comprises a lid memberthat is different than the base and skirt members. The lid member may becomposed of the bimodal polyethylene composition of any one of aspects 1to 5. The base member of the bottle cap or closure containing the lidmember may define an aperture in the base member, wherein the lid membermay be movable from a closed position to an open position such that abottle having the embodiment of the bottle closure having the lid memberattached thereto may be a squeeze bottle, wherein contents of thesqueeze bottle may be contained in the squeeze bottle when the lidmember of the bottle closure is in the closed position and wherein thecontents of the squeeze bottle may be expressed out of the squeezebottle via the aperture in the base member of the bottle closure whenthe lid member of the bottle closure is in the open position.

The bottle cap or closure is made by any suitable technique, includinginjection molding. In an example of the injection molding process, theinventive bimodal polyethylene composition is fed as pellets or powderinto an extruder via a hopper. The extruder conveys, heats, melts, andpressurizes the composition to a form a molten stream thereof. Themolten stream is forced out of the extruder through a nozzle into arelatively cool mold held closed under pressure, thereby filling themold. The melt cools and hardens until fully set-up in the mold. Themold is then opened, and the molded article, e.g. bottle cap or closure,is removed therefrom. The resulting injection molded bottle cap orclosure can close or seal a bottle. When the inner surface of the skirtmember of the bottle cap or closure contains the screw-threading, thebottle cap or closure may be screwed onto the screw-threaded exteriorcap-or-closure-receiving portion of the bottle. To unseal the bottle,the bottle cap or closure may be unscrewed therefrom. The screwing andunscrewing may be performed by a machine or a person.

The bimodal polyethylene composition may further comprise a pigment tocolor the composition. The color may be natural, white, red, blue,yellow, or green.

Activator (for activating procatalysts to form catalysts). Also known asco-catalyst. Any metal containing compound, material or combination ofcompounds and/or substances, whether unsupported or supported on asupport material, that can activate a procatalyst to give a catalyst andan activator species. The activating may comprise, for example,abstracting at least one leaving group (e.g., at least one X in any oneof the structural formulas in FIG. 1) from a metal of a procatalyst(e.g., M in any one of the structural formulas in FIG. 1) to give thecatalyst. The catalyst may be generically named by replacing the leavinggroup portion of the name of the procatalyst with “complex”. Forexample, a catalyst made by activatingbis(2-pentamethylphenylamido)ethyl)amine zirconium dibenzyl may becalled a “bis(2-pentamethylphenylamido)ethyl)amine zirconium complex”. Acatalyst made by activating(tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconiumdichloride or(tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconiumdimethyl may be called a“(tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconiumcomplex”. The catalyst made by activating(tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconiumdichloride may be the same as or different than the catalyst made byactivating(tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconiumdimethyl. The metal of the activator typically is different than themetal of the procatalyst. The molar ratio of metal content of theactivator to metal content of the procatalyst(s) may be from 1000:1 to0.5:1, alternatively 300:1 to 1:1, alternatively 150:1 to 1:1. Theactivator may be a Lewis acid, a non-coordinating ionic activator, or anionizing activator, or a Lewis base, an alkylaluminum, or analkylaluminoxane. The alkylaluminum may be a trialkylaluminum,alkylaluminum halide, or alkylaluminum alkoxide (diethylaluminumethoxide). The trialkylaluminum may be trimethylaluminum,triethylaluminum (“TEAl”), tripropylaluminum, triisobutylaluminum, andthe like. The alkylaluminum halide may be diethylaluminum chloride. Thealkylaluminoxane may be a methyl aluminoxane (MAO), ethyl aluminoxane,or isobutylaluminoxane. The activator may be a MAO that is a modifiedmethylaluminoxane (MMAO). The corresponding activator species may be aderivative of the Lewis acid, non-coordinating ionic activator, ionizingactivator, Lewis base, alkylaluminum, or alkylaluminoxane, respectively.The activator species may have a different structure or composition thanthe activator from which it is derived and may be a by-product of theactivation of the procatalyst or a derivative of the byproduct. Anexample of the derivative of the byproduct is a methylaluminoxanespecies that is formed by devolatilizing during spray-drying of abimodal catalyst system made with methylaluminoxane. The activator maybe commercially available. An activator may be fed into thepolymerization reactor(s) (e.g., one fluidized bed gas phase reactor) ina separate feed from that feeding the reactants used to make the bimodalcatalyst system (e.g., supported bimodal catalyst system) and/or thetrim solution thereinto. The activator may be fed into thepolymerization reactor(s) in “wet mode” in the form of a solutionthereof in an inert liquid such as mineral oil or toluene, in slurrymode as a suspension, or in dry mode as a powder.

Bimodal. Multimodal; having at least 2 peaks, (e.g., 2 or 3 peaks),alternatively only 2 peaks, in a molecular weight distribution (MWD)such as MWD measured by gel permeation chromatography (GPC).

Bimodal catalyst system. A combination of two or more catalyst compoundsindependently useful for enhancing rate of polymerization of a sameolefin monomer and/or comonomer and yields a bimodal polyethylenecomposition. In some aspects the bimodal catalyst system has only twocatalysts, and is prepared from two and only two procatalyst compounds.One of the catalyst compounds may be a metallocene catalyst compound andthe other a non-metallocene catalyst compound. One of the catalystcompounds yields, under the (co)polymerizing conditions, the lowermolecular weight (LMW) polyethylene component and the other catalystcompound yields the higher molecular weight (HMW) polyethylenecomponent. The LMW and HMW polyethylene components together constitutethe bimodal polyethylene composition, which may be the inventive PEcomposition, made with the bimodal catalyst system, and having amultimodal (e.g., bimodal) molecular weight distribution. Typically thebimodal catalyst system, method employing same, and inventive bimodal PEcomposition is free of a Ziegler-Natta catalyst.

The bimodal catalyst system may be made by contacting at least twoprocatalysts having different structures from each other with at leastone of the activators. Each procatalyst may independently comprise ametal atom, at least one ligand bonded to the metal atom, and at leastone leaving group bonded to and displaceable from the metal atom. Eachmetal may be an element of any one of Groups 3 to 14, e.g., a Group 4metal. Each leaving group is H, an unsubstituted alkyl, an aryl group,an aralkyl group, a halide atom, an alkoxy group, or a primary orsecondary amino group. In metallocenes, at least one ligand is acyclopentadienyl or substituted cyclopentadienyl group. Innon-metallocenes, no ligand is a cyclopentadienyl or substitutedcyclopentadienyl group, and instead at least one ligand has at least oneO, N, and/or P atom that coordinates to the metal atom. Typically theligand(s) of the non-metallocene has at least two O, N, and/or P atomsthat coordinates in a multidentate (e.g., bidentate or tridentate)binding mode to the metal atom. Discrete structures means theprocatalysts and catalysts made therefrom have different ligands fromeach other, and either the same or a different metal atom, and eitherthe same or different leaving groups.

One of the procatalysts, useful for making a catalyst of the bimodalcatalyst system and/or making the trim solution, may be a metallocenecompound of any one of formulas (I) to (IX) and another of theprocatalysts may be a non-metallocene of any one of formulas (A) and(B), wherein the formulas are drawn in FIG. 1.

In formula (I), FIG. 1, each of the R¹ to R¹⁰ groups is independently H,a (C₁-C₂₀)alkyl, (C₆-C₂₀)aryl, or (C₇-C₂₀)aralkyl group; M is a Group 4metal; and each X is independently H, a halide, (C₁-C₂₀)alkyl, or(C₇-C₂₀)aralkyl group. In some aspects each of R⁷ to R¹⁰ is H in formula(I).

In formula (II), FIG. 1, each of the R¹ to R⁶ groups is independently H,a (C₁-C₂₀)alkyl, (C₆-C₂₀)aryl, or (C₇-C₂₀)aralkyl group; M is a Group 4metal (e.g., Ti, Zr, or Hf); and each X is independently H, a halide,(C₁-C₂₀)alkyl, or (C₇-C₂₀)aralkyl group.

In formula (III), FIG. 1, each of the R¹ to R¹² groups is independentlyH, a (C₁-C₂₀)alkyl, (C₆-C₂₀)aryl, or (C₇-C₂₀)aralkyl group, wherein atleast one of R⁴ to R⁷ is not H; M is a Group 4 metal (e.g., Ti, Zr, orHf); and each X is independently H, a halide, (C₁-C₂₀)alkyl, or(C₇-C₂₀)aralkyl group. In some aspects each of R⁹ to R¹² is H in formula(III).

In some aspects each X in formulas (I) to (III) is independently ahalide, (C₁-C₄)alkyl, or benzyl; alternatively Cl or benzyl. In someaspects each halide in formulas (I) to (III) is independently Cl, Br, orI; alternatively Cl or Br; alternatively Cl. In some aspects each M informulas (I) to (III) is independently Ti, Zr, or Hf; alternatively Zror Hf; alternatively Ti; alternatively Zr; alternatively Hf.

In formulas (IV) to (IX), FIG. 1, Me is methyl (CH₃), Pr is propyl(i.e., CH₂CH₂CH₃), and each “I” substituent on a ring represents amethyl group.

In formulas (A) and (B), FIG. 1, M is a Group 3 to 12 transition metalatom or a Group 13 or 14 main group metal atom, or a Group 4, 5, or 6metal atom. M may be a Group 4 metal atom, alternatively Ti, Zr, or Hf;alternatively Zr or Hf; alternatively Zr. Each X is independently aleaving group as described above, such as an anionic leaving group.Subscript y is 0 or 1; when y is 0 group L′ is absent. Subscript nrepresents the formal oxidation state of metal atom M and is +3, +4, or+5; alternatively n is +4. L is a Group 15 or 16 element, such asnitrogen or oxygen; L′ is a Group 15 or 16 element or Group 14containing group, such as carbon, silicon or germanium. Y is a Group 15element, such as nitrogen or phosphorus; alternatively nitrogen. Z is aGroup 15 element, such as nitrogen or phosphorus; alternativelynitrogen. Subscript m is 0, −1, −2 or −3; alternatively −2; andrepresents the total formal charge of the Y, Z, and L in formula (A) andthe total formal charge of the Y, Z, and L′ in formula (B). R¹, R², R³,R⁴, R⁵, R⁶, and R⁷ are independently H, a (C₁-C₂₀)hydrocarbyl group, a(C₁-C₂₀)heterohydrocarbyl group, or a (C₁-C₂₀)organoheteryl group,wherein the (C₁-C₂₀)heterohydrocarbyl group and (C₁-C₂₀)organoheterylgroup each independently have at least one heteroatom selected from Si,Ge, Sn, Pb, or P. Alternatively, R¹ and R² are covalently bonded to eachother to form a divalent group of formula —R^(1a)-R^(2a)— and/or R⁴ andR⁵ are covalently bonded to each other to form a divalent group offormula —R^(4a)-R^(5a)—, wherein —R^(1a)-R^(2a)— and —R^(4a)-R^(5a)— areindependently a (C₁-C₂₀)hydrocarbylene group, a(C₁-C₂₀)heterohydrocarbylene group, or a (C₁-C₂₀)organoheterylene group.R³ may be absent; alternatively R³ is H, a halogen atom, a(C₁-C₂₀)hydrocarbyl group, a (C₁-C₂₀)heterohydrocarbyl group, or a(C₁-C₂₀)organoheteryl group. R³ is absent if, for example, L is O, H, oran alkyl group. R⁴ and R⁵ may be a (C₁-C₂₀)alkyl group, a (C₆-C₂₀)arylgroup, a substituted (C₆-C₂₀)aryl group, a (C₃-C₂₀)cycloalkyl group, asubstituted (C₃-C₂₀)cycloalkyl group, a (C₈-C₂₀)bicyclic aralkyl group,or a substituted (C₈-C₂₀)bicyclic aralkyl group. R⁶ and R ⁷ may be H orabsent. R* may be absent, or may be a hydrogen, a Group 14 atomcontaining group, a halogen, or a heteroatom containing group.

In some aspects the bimodal catalyst system may comprise a combinationof a metallocene catalyst compound and a non-metallocene catalystcompound. The metallocene catalyst compound may be a metalloceneligand-metal complex such as a metallocene ligand-Group 4 metal complex,which may be made by activating (with the activator) a procatalystcompound selected from(pentamethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconiumdichloride, bis(n-butylcyclopentadienyl)zirconium dichloride,(pentamethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconiumdimethyl, and bis(n-butylcyclopentadienyl)zirconium dimethyl. Thenon-metallocene catalyst compound may be a non-metallocene ligand-metalcomplex such as a non-metallocene ligand-Group 4 metal complex, whichmay be made by activating (with the activator) a procatalyst compoundselected from bis(2-(2,4,6-trimethylphenylamido)ethyl)amine zirconiumdibenzyl and bis(2-(pentamethylphenylamido)ethyl)amine zirconiumdibenzyl.

In some aspects the bimodal catalyst system may be made by activating,according to the method of contacting with an activator, a combinationof a metallocene procatalyst compound that is(tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconiumdichloride and a non-metallocene procatalyst compound that isbis(2-pentamethylphenylamido)ethyl)amine zirconium dibenzyl. The(tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconiumdichloride is a compound of formula (II) wherein M is Zr, each X is Cl,R⁶ is propyl (CH₂CH₂CH₃), and each of R¹ to R⁴ is methyl. Thebis(2-pentamethylphenylamido)ethyl)amine zirconium dibenzyl is aprocatalyst compound of formula (A) wherein M is Zr, each X is benzyl,R¹ and R² are each CH₂CH₂; R³ is H; L, Y, and Z are all N; and R⁴ and R⁵are each pentamethylphenyl; and R⁶ and R⁷ are absent.

Each of the catalyst compounds of the bimodal catalyst systemindependently may be unsupported, alternatively supported on a supportmaterial, in which latter case the bimodal catalyst system is asupported catalyst system. When each catalyst compound is supported, thecatalyst compounds may reside on the same support material (e.g., sameparticles), or on different support materials (e.g., differentparticles). The bimodal catalyst system includes mixtures of unsupportedcatalyst compounds in slurry form and/or solution form. The supportmaterial may be a silica (e.g., fumed silica), alumina, a clay, or talc.The fumed silica may be hydrophilic (untreated), alternativelyhydrophobic (treated). In some aspects the support is the hydrophobicfumed silica, which may be prepared by treating an untreated fumedsilica with a treating agent such as dimethyldichlorosilane, apolydimethylsiloxane fluid, or hexamethyldisilazane. In some aspects thetreating agent is dimethyldichlorosilane.

In some aspects the bimodal catalyst system is the bimodal catalystsystem described in any one of the following references: U.S. Pat. Nos.7,193,017 B2; 7,312,279 B2; 7,858,702 B2; 7,868,092 B2; 8,202,940 B2;and 8,378,029 B2 (e.g., column 4/line 60 to column 5/line 10 and column10/lines 6 to 38 and Example 1).

The bimodal catalyst system may be fed into the polymerizationreactor(s) in “dry mode” or “wet mode”, alternatively dry mode,alternatively wet mode. The dry mode is fed in the form of a dry powderor granules. The wet mode is fed in the form of a suspension of thebimodal catalyst system in an inert liquid such as mineral oil. Thebimodal catalyst system is commercially available under the PRODIGY™Bimodal Catalysts brand, e.g., BMC-200, from Univation Technologies,LLC.

(C₃-C₂₀)alpha-olefin. A compound of formula (I): H₂C═C(H)—R (I), whereinR is a straight chain (C₁-C₁₈)alkyl group. (C₁-C₁₈)alkyl group is amonovalent unsubstituted saturated hydrocarbon having from 1 to 18carbon atoms. Examples of R are methyl, ethyl, propyl, butyl, pentyl,hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl,tetradecyl, pentadecyl, hexadecyl, heptadecyl, and octadecyl. In someembodiments the (C₃-C₂₀)alpha-olefin is 1-propene, 1-butene, 1-hexene,or 1-octene; alternatively 1-butene, 1-hexene, or 1-octene;alternatively 1-butene or 1-hexene; alternatively 1-butene or 1-octene;alternatively 1-hexene or 1-octene; alternatively 1-butene;alternatively 1-hexene; alternatively 1-octene; alternatively acombination of any two of 1-butene, 1-hexene, and 1-octene. The(C₃-C₂₀)alpha-olefin is used as a comonomer from which the comonomericunits of the LMW polyethylene component are derived may be the same as,alternatively different than, the(C₃-C₂₀)alpha-olefin from which thecomonomeric units of the HMW polyethylene component are derived.

Consisting essentially of, consist(s) essentially of, and the like.Partially-closed ended expressions that exclude anything that wouldaffect the basic and novel characteristics of that which they describe,but otherwise allow anything else. As applied to the description of abimodal catalyst system embodiment consisting essentially ofbis(2-pentamethylphenylamido)ethyl)amine zirconium dibenzyl and(tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconiumdichloride, both disposed on a solid support and activated with anactivating agent, the expression means the embodiment does not contain aZiegler-Natta catalyst or any organic ligand other than thebis(2-pentamethylphenylamido)ethyl)amine, benzyl,tetramethylcyclopentadienyl, and n-propylcyclopentadienyl ligands. Oneor more of the benzyl and chloride leaving groups may be absent from theZr in the bimodal catalyst system. The expression “consistingessentially of” as applied to the description of the “trim solutionmeans the trim solution is unsupported (i.e., not disposed on aparticulate solid) and is free of a Ziegler-Natta catalyst or anyorganic ligand other than the tetramethylcyclopentadienyl andn-propylcyclopentadienyl ligands. The expression “consist essentiallyof” as applied to a dry inert purge gas means that the dry inert purgegas is free of, alternatively has less than 5 parts per million based ontotal parts by weight of gas of water or any reactive compound thatcould oxidize a constituent of the present polymerization reaction. Insome aspects any one, alternatively each “comprising” or “comprises” maybe replaced by “consisting essentially of” or “consists essentially of”,respectively; alternatively by “consisting of” or “consists of”,respectively.

Consisting of and consists of. Closed ended expressions that excludeanything that is not specifically described by the limitation that itmodifies. In some aspects any one, alternatively each expression“consisting essentially of” or “consists essentially of” may be replacedby the expression “consisting of” or “consists of”, respectively.

(Co)polymerizing conditions. Any result effective variable orcombination of such variables, such as catalyst composition; amount ofreactant; molar ratio of two reactants; absence of interfering materials(e.g., H₂O and O₂); or a process parameter (e.g., feed rate ortemperature), step, or sequence that is effective and useful for theinventive copolymerizing method in the polymerization reactor(s) to givethe inventive bimodal PE composition.

At least one, alternatively each of the (co)polymerizing conditions maybe fixed (i.e., unchanged) during production of the inventive bimodal PEcomposition. Such fixed (co)polymerizing conditions may be referred toherein as steady-state (co)polymerizing conditions. Steady-state(co)polymerizing conditions are useful for continuously makingembodiments of the inventive bimodal PE composition having same polymerproperties.

Alternatively, at least one, alternatively two or more of the(co)polymerizing conditions may be varied within their defined operatingparameters during production of the inventive bimodal PE composition inorder to transition from the production of a first embodiment of theinventive bimodal PE composition having a first set of polymerproperties to a non-inventive bimodal PE composition or to a secondembodiment of the inventive bimodal PE composition having a second setof polymer properties, wherein the first and second sets of polymerproperties are different and are each within the limitations describedherein for the inventive bimodal PE composition. For example, all other(co)polymerizing conditions being equal, a higher molar ratio of(C₃-C₂₀)alpha-olefin comonomer/ethylene feeds in the inventive method ofcopolymerizing produces a lower density of the resulting productinventive bimodal PE composition. At a given molar ratio ofcomonomer/ethylene, the molar ratio of the procatalyst of the trimsolution relative to total moles of catalyst compounds of the bimodalcatalyst system may be varied to adjust the density, melt index, meltflow, molecular weight, and/or melt flow ratio thereof. To illustrate anapproach to making transitions, perform one of the later describedinventive copolymerization examples to reach steady-state(co)polymerizing conditions. Then change one of the (co)polymerizingconditions to begin producing a new embodiment of the inventive bimodalPE composition. Sample the new embodiment, and measure a propertythereof. If necessary, repeat the change condition/sampleproduct/measure property steps at intervals until the measurement showsthe desired value for the property is obtained. An example of suchvarying of an operating parameter includes varying the operatingtemperature within the aforementioned range from 83° to 87° C. such asby changing from a first operating temperature of 85° C. to a secondoperating temperature of 86° C., or by changing from a third operatingtemperature of 87° C. to a third operating temperature of 85° C.Similarly, another example of varying an operating parameter includesvarying the molar ratio of molecular hydrogen to ethylene (H2/C2) from0.017 to 0.018, or from 0.020 to 0.019. Similarly, another example ofvarying an operating parameter includes varying the molar ratio ofcomonomer (Comer) to the ethylene (Comer/C2 molar ratio) from 0.028 to0.038, or from 0.041 to 0.025. Combinations of two or more of theforegoing example variations are included herein. Transitioning from oneset to another set of the (co)polymerizing conditions is permittedwithin the meaning of “(co)polymerizing conditions” as the operatingparameters of both sets of (co)polymerizing conditions are within theranges defined therefore herein. A beneficial consequence of theforegoing transitioning is that any described property value for theinventive bimodal PE composition, or the LMW or HMW polyethylenecomponent thereof, may be achieved by a person of ordinary skill in theart in view of the teachings herein.

The (co)polymerizing conditions may further include a high pressure,liquid phase or gas phase polymerization reactor and polymerizationmethod to yield the inventive bimodal PE composition. Such reactors andmethods are generally well-known in the art. For example, the liquidphase polymerization reactor/method may be solution phase or slurryphase such as described in U.S. Pat. No. 3,324,095. The gas phasepolymerization reactor/method may employ the induced condensing agentand be conducted in condensing mode polymerization such as described inU.S. Pat. Nos. 4,453,399; 4,588,790; 4,994,534; 5,352,749; 5,462,999;and 6,489,408. The gas phase polymerization reactor/method may be afluidized bed reactor/method as described in U.S. Pat. Nos. 3,709,853;4,003,712; 4,011,382; 4,302,566; 4,543,399; 4,882,400; 5,352,749;5,541,270; EP-A-0 802 202; and Belgian Patent No. 839,380. These patentsdisclose gas phase polymerization processes wherein the polymerizationmedium is either mechanically agitated or fluidized by the continuousflow of the gaseous monomer and diluent. Other gas phase processescontemplated include series or multistage polymerization processes suchas described in U.S. Pat. Nos. 5,627,242; 5,665,818; 5,677,375; EP-A-0794 200; EP-B1-0 649 992; EP-A-0 802 202; and EP-B-634421.

The (co)polymerizing conditions for gas or liquid phase reactors/methodsmay further include one or more additives such as a chain transferagent, a promoter, or a scavenging agent. The chain transfer agents arewell known and may be alkyl metal such as diethyl zinc. Promoters arewell known such as in U.S. Pat. No. 4,988,783 and may includechloroform, CFCl3, trichloroethane, and difluorotetrachloroethane.Scavenging agents may be a trialkylaluminum. Slurry or gas phasepolymerizations may be operated free of (not deliberately added)scavenging agents. The (co)polymerizing conditions for gas phasereactors/polymerizations may further include an amount (e.g., 0.5 to 200ppm based on all feeds into reactor) static control agents and/orcontinuity additives such as aluminum stearate or polyethyleneimine.Static control agents may be added to the gas phase reactor to inhibitformation or buildup of static charge therein.

The (co)polymerizing conditions may further include using molecularhydrogen to control final properties of the LMW and/or HMW polyethylenecomponents or inventive bimodal PE composition. Such use of H₂ isgenerally described in Polypropylene Handbook 76-78 (Hanser Publishers,1996). All other things being equal, using hydrogen can increase themelt flow rate or melt index thereof, which are influenced by theconcentration of hydrogen. A molar ratio of hydrogen to total monomer(H₂/monomer), hydrogen to ethylene (H₂/C₂), or hydrogen to comonomer(H₂/α-olefin) may be from 0.0001 to 10, alternatively 0.0005 to 5,alternatively 0.001 to 3, alternatively 0.001 to 0.10.

The (co)polymerizing conditions may include a partial pressure ofethylene in the polymerization reactor(s) independently from 690 to 3450kilopascals (kPa, 100 to 500 pounds per square inch absolute (psia),alternatively 1030 to 2070 kPa (150 to 300 psia), alternatively 1380 to1720 kPa (200 to 250 psia), alternatively 1450 to 1590 kPa (210 to 230psia), e.g., 1520 kPa (220 psia). 1.000 psia=6.8948 kPa.

Dry. Generally, a moisture content from 0 to less than 5 parts permillion based on total parts by weight. Materials fed to thepolymerization reactor(s) during a polymerization reaction under(co)polymerizing conditions typically are dry.

Ethylene. A compound of formula H₂C═CH₂. A polymerizable monomer.

Feeds. Quantities of reactants and/or reagents that are added or “fed”into a reactor. In continuous polymerization operation, each feedindependently may be continuous or intermittent. The quantities or“feeds” may be measured, e.g., by metering, to control amounts andrelative amounts of the various reactants and reagents in the reactor atany given time.

Film: for claiming, measure properties on 25 micrometers thick monolayerfilms.

Higher molecular weight (HMW). Relative to LMW, having a higher weightaverage molecular weight (M_(w)). The HMW polyethylene component of theinventive bimodal PE composition may have an M_(w) from 10,000 to1,000,000 g/mol. The lower endpoint of the M_(w) for the HMWpolyethylene component may be 100,000, alternatively 200,000 g/mol,alternatively 300,000 g/mol. The upper endpoint of M_(w) may be 900,000,alternatively 600,000, alternatively 400,000 g/mol. In describing theinventive bimodal PE composition, the bottom portion of the range ofM_(w) for the HMW polyethylene component may overlap the upper portionof the range of M_(w) for the LMW polyethylene component, with theproviso that in any embodiment of the inventive bimodal PE compositionthe particular M_(w) for the HMW polyethylene component is greater thanthe particular M_(w) for the LMW polyethylene component. The HMWpolyethylene component may be made with catalyst prepared by activatinga non-metallocene ligand-Group 4 metal complex.

Inert. Generally, not (appreciably) reactive or not (appreciably)interfering therewith in the inventive polymerization reaction. The term“inert” as applied to the purge gas or ethylene feed means a molecularoxygen (O₂) content from 0 to less than 5 parts per million based ontotal parts by weight of the purge gas or ethylene feed.

Induced condensing agent (ICA). An inert liquid useful for coolingmaterials in the polymerization reactor(s) (e.g., a fluidized bedreactor). In some aspects the ICA is a (C₅-C₂₀)alkane, alternatively a(C₁₁-C₂₀)alkane, alternatively a (C₅-C₁₀)alkane. In some aspects the ICAis a (C₅-C₁₀)alkane. In some aspects the (C₅-C₁₀)alkane is a pentane,e.g., normal-pentane or isopentane; a hexane; a heptane; an octane; anonane; a decane; or a combination of any two or more thereof. In someaspects the ICA is isopentane (i.e., 2-methylbutane). The inventivemethod of polymerization, which uses the ICA, may be referred to hereinas being an inert condensing mode operation (ICMO). Concentration in gasphase measured using gas chromatography by calibrating peak area percentto mole percent (mol %) with a gas mixture standard of knownconcentrations of ad rem gas phase components. Concentration may be from1 to 10 mol %, alternatively from 3 to 8 mole %. The use of ICA isoptional. In some aspects, including some of the inventive examplesdescribed later, an ICA is used. For example, in aspects of the methodof making a mixture of ICA and catalyst may be fed into a polymerizationreactor. In other aspects of the method, use of ICA may be omitted, anda mixed pre-formulated dry catalyst may be fed as such into thepolymerization reactor, which lacks ICA.

Lower molecular weight (LMW). Relative to HMW, having a lower weightaverage molecular weight (M_(w)). The LMW polyethylene component of theinventive bimodal PE composition may have an M_(w) from 3,000 to 100,000g/mol. The lower endpoint of the M_(w) for the LMW polyethylenecomponent may be 5,000, alternatively 8,000, alternatively 10,000,alternatively 11,000 g/mol. The upper endpoint of M_(w) may be 50,000,alternatively 40,000, alternatively 30,000, alternatively 20,000 g/mol.The LMW polyethylene component may be made with catalyst prepared byactivating a metallocene ligand-Group 4 metal complex.

Polyethylene. A macromolecule, or collection of macromolecules, composedof repeat units wherein 50 to 100 mole percent (mol %), alternatively 70to 100 mol %, alternatively 80 to 100 mol %, alternatively 90 to 100 mol%, alternatively 95 to 100 mol %, alternatively any one of the foregoingranges wherein the upper endpoint is <100 mol %, of such repeat unitsare derived from ethylene monomer, and, in aspects wherein there areless than 100 mol % ethylenic repeat units, the remaining repeat unitsare comonomeric units derived from at least one (C₃-C₂₀)alpha-olefin; orcollection of such macromolecules. Linear medium density polyethylene(PE). The macromolecule having a substantially linear structure.

Procatalyst. Also referred to as a precatalyst or catalyst compound (asopposed to active catalyst compound), generally a material, compound, orcombination of compounds that exhibits no or extremely lowpolymerization activity (e.g., catalyst efficiency may be from 0 or<1,000) in the absence of an activator, but upon activation with anactivator yields a catalyst that shows at least 10 times greatercatalyst efficiency than that, if any, of the procatalyst.

Resolved (GPC chromatogram). A molecular weight distribution having twopeaks separated by an intervening local minimum. For example, a resolvedGPC chromatogram of the inventive polymers represented by a plot of dW/dlog(MW) versus log(MW) that features local maxima dW/d log(MW) valuesfor the LMW and HMW polyethylene component peaks, and a local minimumdW/d log(MW) value at a log(MW) between the maxima. The at least someseparation of the peaks for the LMW and HMW polyethylene components inthe chromatogram of the GPC. Typically the separation may not be down tobaseline.

Start-up or restart of the polymerization reactor(s) illustrated with afluidized bed reactor. The start-up of a recommissioned fluidized bedreactor (cold start) or restart of a transitioning fluidized bed reactor(warm start/transition) includes a time period that is prior to reachingthe (co)polymerizing conditions. Start-up or restart may include the useof a seedbed preloaded or loaded, respectively, into the fluidized bedreactor. The seedbed may be composed of powder of polyethylene. Thepolyethylene of the seedbed may be a MDPE, alternatively a PE,alternatively a bimodal PE, alternatively a previously made embodimentof the inventive bimodal PE composition.

Start-up or restart of the fluidized bed reactor may also include gasatmosphere transitions comprising purging air or other unwanted gas(es)from the reactor with a dry (anhydrous) inert purge gas, followed bypurging the dry inert purge gas from the reactor with dry ethylene gas.The dry inert purge gas may consist essentially of molecular nitrogen(N₂), argon, helium, or a mixture of any two or more thereof. When notin operation, prior to start-up (cold start), the fluidized bed reactorcontains an atmosphere of air. The dry inert purge gas may be used tosweep the air from a recommissioned fluidized bed reactor during earlystages of start-up to give a fluidized bed reactor having an atmosphereconsisting of the dry inert purge gas. Prior to restart (e.g., after achange in seedbeds or prior to a change in alpha-olefin comonomer), atransitioning fluidized bed reactor may contain an atmosphere ofunwanted alpha-olefin, unwanted ICA or other unwanted gas or vapor. Thedry inert purge gas may be used to sweep the unwanted vapor or gas fromthe transitioning fluidized bed reactor during early stages of restartto give the fluidized bed reactor having an atmosphere consisting of thedry inert purge gas. Any dry inert purge gas may itself be swept fromthe fluidized bed reactor with the dry ethylene gas. The dry ethylenegas may further contain molecular hydrogen gas such that the dryethylene gas is fed into the fluidized bed reactor as a mixture thereof.Alternatively the dry molecular hydrogen gas may be introducedseparately and after the atmosphere of the fluidized bed reactor hasbeen transitioned to ethylene. The gas atmosphere transitions may bedone prior to, during, or after heating the fluidized bed reactor to thereaction temperature of the (co)polymerizing conditions.

Start-up or restart of the fluidized bed reactor also includesintroducing feeds of reactants and reagents thereinto. The reactantsinclude the ethylene and the alpha-olefin. The reagents fed into thefluidized bed reactor include the molecular hydrogen gas and,optionally, the induced condensing agent (ICA) and the mixture of thebimodal catalyst system and the trim solution.

Trim solution. Any one of the metallocene procatalyst compounds or thenon-metallocene procatalyst compounds described earlier dissolved in theinert liquid solvent (e.g., liquid alkane). The trim solution is mixedwith the bimodal catalyst system to make the mixture, and the mixture isused in the inventive polymerization reaction to modify at least oneproperty of the inventive bimodal PE composition made thereby. Examplesof such at least one property are density, melt index I₂, flow indexI₂₁, melt flow ratio (I₂₁/I₂), and molecular mass dispersity(M_(w)/M_(n)), Ð_(M). The mixture of the bimodal catalyst system and thetrim solution may be fed into the polymerization reactor(s) in “wetmode”, alternatively may be devolatilized and fed in “dry mode”. The drymode is fed in the form of a dry powder or granules. When mixturecontains a solid support, the wet mode is fed in the form of asuspension or slurry. In some aspects the inert liquid is a liquidalkane such as heptane.

Ziegler-Natta catalysts. Heterogeneous materials that enhance olefinpolymerization reaction rates and typically are products that areprepared by contacting inorganic titanium compounds, such as titaniumhalides supported on a magnesium chloride support, with an activator.The activator may be an alkylaluminum activator such as triethylaluminum(TEA), triisobutylaluminum (TIBA), diethylaluminum chloride (DEAC),diethylaluminum ethoxide (DEAE), or ethylaluminum dichloride (EADC).

A compound includes all its isotopes and natural abundance andisotopically-enriched forms. The enriched forms may have medical oranti-counterfeiting uses.

In some aspects any compound, composition, formulation, mixture, orreaction product herein may be free of any one of the chemical elementsselected from the group consisting of: H, Li, Be, B, C, N, O, F, Na, Mg,Al, Si, P, S, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge,As, Se, Br, Rb, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb,Te, I, Cs, Ba, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Tl, Pb, Bi,lanthanoids, and actinoids; with the proviso that chemical elementsrequired by the compound, composition, formulation, mixture, or reactionproduct (e.g., C and H required by a polyolefin or C, H, and O requiredby an alcohol) are not excluded.

The following apply unless indicated otherwise. Alternatively precedes adistinct embodiment. ASTM means the standards organization, ASTMInternational, West Conshohocken, Pa., USA. IEC means the standardsorganization, International Electrotechnical Commission, Geneva,Switzerland. ISO means the standards organization, InternationalOrganization for Standardization, Geneva, Switzerland. Any comparativeexample is used for illustration purposes only and shall not be priorart. Free of or lacks means a complete absence of; alternatively notdetectable. IUPAC is International Union of Pure and Applied Chemistry(IUPAC Secretariat, Research Triangle Park, N.C., USA). May confers apermitted choice, not an imperative. Operative means functionallycapable or effective. Optional(ly) means is absent (or excluded),alternatively is present (or included). Properties are measured using astandard test method and conditions for the measuring (e.g., viscosity:23° C. and 101.3 kPa). Ranges include endpoints, subranges, and wholeand/or fractional values subsumed therein, except a range of integersdoes not include fractional values. Room temperature: 23° C.±1° C.Substituted when referring to a compound means having, in place ofhydrogen, one or more substituents, up to and including persubstitution.

Bimodality Test Method: determine presence or absence of resolvedbimodality by plotting dWf/d Log M (mass detector response) on y-axisversus Log M on the x-axis to obtain a GPC chromatogram curve containinglocal maxima log(MW) values for LMW and HMW polyethylene componentpeaks, and observing the presence or absence of a local minimum betweenthe LMW and HMW polyethylene component peaks. The dWf is change inweight fraction, d Log M is also referred to as d Log(MW) and is changein logarithm of molecular weight, and Log M is also referred to asLog(MW) and is logarithm of molecular weight.

Deconvoluting Test Method: segment the chromatogram obtained using theBimodality Test Method into nine (9) Schulz-Flory molecular weightdistributions. Such deconvolution method is described in U.S. Pat. No.6,534,604. Assign the lowest four MW distributions to the LMWpolyethylene component and the five highest MW distributions to the HMWpolyethylene component. Determine the respective weight percents (wt %)for each of the LMW and HMW polyethylene components in the inventivebimodal PE composition by using summed values of the weight fractions(Wf) of the LMW and HMW polyethylene components and the respectivenumber average molecular weights (M_(n)) and weight average molecularweights (M_(w)) by known mathematical treatment of aggregatedSchulz-Flory MW distributions.

Density Test Method: measured according to ASTM D792-13, Standard TestMethods for Density and Specific Gravity (Relative Density) of Plasticsby Displacement, Method B (for testing solid plastics in liquids otherthan water, e.g., in liquid 2-propanol). Report results in units ofgrams per cubic centimeter (g/cm³).

Environmental Stress Crack Resistance (ESCR) F50 Test Method: measuredaccording to ASTM D1693-15, Standard Test Method for EnvironmentalStress-Cracking of Ethylene Plastics, Method B. Igepal CO-630 is used at10 wt % in water at 50° C. Igepal CO-630 (CAS No. 68412-54-4) is apolyoxyethylene nonylphenyl ether, branched, wherein the polyoxyethyleneis of linear formula (C₂H₄O)_(n), wherein subscript m is on average from9 to 10; and has a number average molecular weight of 617 g/mol. Testingis carried out on 10 (or more) molded specimens having a thickness ofeither 0.32 cm (⅛ inch) or 1.94 cm (¾ inch), a length of 3.81 cm (1.5inch), and width of 1.27 cm (0.5 inch). The thickness of each specimenis 0.191 cm (0.075 inch), as per ASTM D1693-15, Method B. The lengthdefines a long axis of the test specimen. Using a mounted razor blade, asurface cut of specified length and depth is made on the test specimenparallel to its long axis. The resulting cut specimens are then stressedby being bent at 180 degrees, and then the bent specimens are placed ina rack that is immersed in a test tube containing the 10 wt % IgepalCO-630 in water at 50° C. Periodically the immersed specimens arevisually inspected for cracks perpendicular to the cuts, and the numberof failures (the number of test specimens having perpendicular cracks)is recorded. The test failure point is when half of the total number oftest specimens shows cracking in direction perpendicular to the cuts.The length of time in hours that has elapsed from initial immersion tothe test failure point is recorded as the ESCR F50.

Flow Index (190° C., 5.0 kg, “I₅”) Test Method: use ASTM D1238-13,Standard Test Method for Melt Flow Rates of Thermoplastics by ExtrusionPlatometer, using conditions of 190° C./5.0 kilograms (kg). Reportresults in units of grams eluted per 10 minutes (g/10 min.) or theequivalent in decigrams per 1.0 minute (dg/1 min.).

High-Load Flow Index (190° C., 21.6 kg, “I₂₁”) Test Method: use ASTMD1238-13, Standard Test Method for Melt Flow Rates of Thermoplastics byExtrusion Platometer, using conditions of 190° C./21.6 kg. Reportresults in units of grams eluted per 10 minutes (g/10 min.) or theequivalent in decigrams per 1.0 minute (dg/1 min.).

Gel permeation chromatography (GPC) Method: Weight-Average MolecularWeight Test Method: determine M_(w), number average molecular weight(M_(n)), and M_(w)/M_(n) using chromatograms obtained on a HighTemperature Gel Permeation Chromatography instrument (HTGPC, PolymerLaboratories). The HTGPC is equipped with transfer lines, a differentialrefractive index detector (DRI), and three Polymer Laboratories PLgel 10μm Mixed-B columns, all contained in an oven maintained at 160° C.Method uses a solvent composed of BHT-treated TCB at nominal flow rateof 1.0 milliliter per minute (mL/min.) and a nominal injection volume of300 microliters (μL). Prepare the solvent by dissolving 6 grams ofbutylated hydroxytoluene (BHT, antioxidant) in 4 liters (L) of reagentgrade 1,2,4-trichlorobenzene (TCB), and filtering the resulting solutionthrough a 0.1 micrometer (μm) Teflon filter to give the solvent. Degasthe solvent with an inline degasser before it enters the HTGPCinstrument. Calibrate the columns with a series of monodispersedpolystyrene (PS) standards. Separately, prepare known concentrations oftest polymer dissolved in solvent by heating known amounts thereof inknown volumes of solvent at 160° C. with continuous shaking for 2 hoursto give solutions. (Measure all quantities gravimetrically.) Targetsolution concentrations, c, of test polymer of from 0.5 to 2.0milligrams polymer per milliliter solution (mg/mL), with lowerconcentrations, c, being used for higher molecular weight polymers.Prior to running each sample, purge the DRI detector. Then increase flowrate in the apparatus to 1.0 mL/min/, and allow the DRI detector tostabilize for 8 hours before injecting the first sample. Calculate M_(w)and M_(n) using universal calibration relationships with the columncalibrations. Calculate MW at each elution volume with followingequation:

${{\log \; M_{X}} = {\frac{\log \left( {K_{X}/K_{PS}} \right)}{a_{X} + 1} + {\frac{a_{PS} + 1}{a_{X} + 1}\log \; M_{PS}}}},$

where subscript “X” stands for the test sample, subscript “PS” standsfor PS standards, a_(PS)=0.67 , K_(PS)=0.000175 , and a_(x) and K_(x)are obtained from published literature. For polyethylenes,a_(x)/K_(x)=0.695/0.000579. For polypropylenesa_(x)/K_(x)=0.705/0.0002288. At each point in the resultingchromatogram, calculate concentration, c, from a baseline-subtracted DRIsignal, I_(DRI), using the following equation: c=K_(DRI)I_(DRI)/(dn/dc),wherein K_(DRI) is a constant determined by calibrating the DRI, /indicates division, and dn/dc is the refractive index increment for thepolymer. For polyethylene, dn/dc=0.109. Calculate mass recovery ofpolymer from the ratio of the integrated area of the chromatogram ofconcentration chromatography over elution volume and the injection masswhich is equal to the pre-determined concentration multiplied byinjection loop volume. Report all molecular weights in grams per mole(g/mol) unless otherwise noted. Further details regarding methods ofdetermining Mw, Mn, MWD are described in US 2006/0173123 page 24-25,paragraphs [0334] to [0341]. Plot of dW/d Log(MW) on the y-axis versusLog(MW) on the x-axis to give a GPC chromatogram, wherein Log(MW) anddW/d Log(MW) are as defined above.

Long Chain Branching (LCB) Test Method: calculate number of long chainbranches (LCB) per 1,000 carbon atoms of a test polymer using acorrelation developed by Janzen and Colby (J. Mol. Struct., 485/486,569-584 (1999)) between zero shear viscosity, η_(o), and M_(w). Theircorrelation is drawn as a reference line on a reference graph of η_(o)on the y-axis and M_(w) on the x-axis. Then a test polymer ischaracterized by (a) and (b): (a) using the Zero Shear ViscosityDetermination Method described later, measuring the test polymer'ssmall-strain (10%) oscillatory shear, and using a three parameterCarreau-Yasuda empirical model (“CY Model”) to determine values forη_(o) therefrom; and (b) using the GPC Test Method described earlier,measuring the test polymer's M_(w). Plot the results for the testpolymer's η_(o) and M_(w) on the reference graph, and compare them tothe reference line. Results for test polymers with zero (0) long chainbranching per 1,000 carbon atoms will plot below the Janzen and Colbyreference line, whereas results for test polymers having long chainbranching >0 per 1,000 carbon atoms will plot above the Janzen and Colbyreference line. The CY Model is well-known from R. B. Bird, R. C.Armstrong, & O. Hasseger, Dynamics of Polymeric Liquids, Volume 1, FluidMechanics, 2^(nd) Edition, John Wiley & Sons, 1987; C. A. Hieber & H. H.Chiang, Rheol. Acta, 1989, 28: 321; and C. A. Hieber & H. H. Chiang,Polym. Eng. Sci., 1992, 32: 931.

Melt Flow Ratio (190° C., “I₂₁/I₂”) Test Method: calculated by dividingthe value from the Flow Index I₂₁ Test Method by the value from the MeltIndex I₂ Test Method.

Melt Index (190° C., 2.16 kilograms (kg), “I₂”) Test Method: forethylene-based (co)polymer is measured according to ASTM D1238-13, usingconditions of 190° C./2.16 kg, formerly known as “Condition E” and alsoknown as I₂. Report results in units of grams eluted per 10 minutes(g/10 min.) or the equivalent in decigrams per 1.0 minute (dg/1 min.).10.0 dg=1.00 g. Melt index is inversely proportional to the weightaverage molecular weight of the polyethylene, although the inverseproportionality is not linear. Thus, the higher the molecular weight,the lower the melt index.

Oxidative Induction Time (OIT) Test Method (O₂, 210° C.): Measures thetime required to initiate oxidation of a test sample of a polyolefincomposition, made by the Compression Molded Plaque Preparation Method,under molecular oxygen atmosphere at 210° C. in a differential scanningcalorimeter (DSC). Used TA Instruments Thermal Analysis Q-1000 DSC unitequipped with a Module DSC Standard Cell. Cut approximately 2 mg of testsample into thin slices using a razor blade. Placed sliced test sampleinto an open aluminum DSC pan. Equilibrated pan/contents at 60° C. for 5minutes under nitrogen gas flowing at 50 milliliters per minute(mL/min.). Then under nitrogen gas raised the temperature at 20° C./min.to 210° C., and held at 210° C. for 5 minutes under nitrogen. Thenswitched the gas over to molecular oxygen, also at a flow rate of 50mL/min., and recorded the elapsed time in minutes from when the oxygengas was switched on (Time 0) to the onset of a significant exothermicpeak in DSC as the oxidative induction time or OIT (O₂, 210° C.). Thelonger the elapsed time to OIT (O₂, 210° C.), the more resistant tooxidative heat aging the test sample.

Shrinkage: measured by ASTM D-955 using a 60 mm×60 mm×2 mm plaques.

Spiral Flow Length Test Method: perform spiral flow length measurementsby molding a polymer sample on an injection molding machine into aspiral flow mold having thickness of 0.127 centimeter (cm, 0.05 inch),at the melt temperature of 260° C. and a mold temperature of 26° C.under the injection pressures of 68.95 MPa (10,000 psi), 103.4 MPa(15,000 psi) and 137.9 MPa (20,000 psi). Measure the flow length of thepolymer into the mold in centimeters. Calculate a mean from five valuesat each pressure setting for each polymer molded. The spiral flow of athermosetting molding compound is a measure of its combinedcharacteristics of fusion under pressure, melt viscosity, and gelationrate under the specified conditions.

Zero Shear Viscosity Determination Method: perform small-strain (10%)oscillatory shear measurements on polymer melts at 190° C. using anARES-G2 Advanced Rheometric Expansion System, from TA Instruments, withparallel-plate geometry to obtain complex viscosity |η*| versusfrequency (ω) data. Determine values for the three parameters—zero shearviscosity, η_(o), characteristic viscous relaxation time, τ_(η), and thebreadth parameter, a,—by curve fitting the obtained data using thefollowing CY Model:

${{{\eta^{*}(\omega)}} = \frac{\eta\bullet}{\left\lbrack {1 + \left( {\tau_{\eta}\omega} \right)^{a}} \right\rbrack^{\frac{({1 - n})}{a}}}},$

wherein |η*(ω)| is magnitude of complex viscosity, η_(o) is zero shearviscosity, τ_(η) is viscous relaxation time, a is the breadth parameter,n is power law index, and ω is angular frequency of oscillatory shear.

Bimodal catalyst system 1: consisted essentially of or made frombis(2-pentamethylphenylamido)ethyl)amine zirconium dibenzyl and(tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconiumdichloride spray-dried in a 3:1 molar ratio onto CAB-O-SIL TS610, ahydrophobic fumed silica made by surface treating hydrophilic(untreated) fumed silica with dimethyldichlorosilane support, andmethylaluminoxane (MAO), and fed into a gas phase polymerization reactoras a slurry in mineral oil. The molar ratio of moles MAO to (moles ofbis(2-pentamethylphenylamido)ethyl)amine zirconium dibenzyl+moles(tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconiumdichloride) was 140:1.

Comonomer 1: 1-Hexene, used at a molar ratio of 1-hexene/C2 in Table 1.

Ethylene (“02”): partial pressure of C2 was maintained as describedlater in Table 1.

Induced condensing agent 1 (“ICA1”): isopentane, used at a mole percent(mol %) concentration in the gas phase of a gas phase reactor relativeto the total molar content of gas phase matter. Reported later in Table1.

Molecular hydrogen gas (“H2”): used at a molar ratio of H2/C2 in Table1.

Trim solution 1: consisted essentially of or made from(tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconiumdimethyl (procatalyst) dissolved in heptane to give a solution having aconcentration of 0.7 gram procatalyst per milliliter solution (g/mL).

Inventive Examples 1 and 2 (IE1 & IE2): Produced the bimodal PEcomposition of IE1 in a single gas phase polymerization reactorcontaining a pilot plant scale continuous mode, gas phase fluidized bedreactor with a capacity of producing 22 to 110 kg resin per hour. For anexperimental run, preloaded the reactor before startup with a seedbed ofgranular resin inside. Dried down the reactor with the seedbed below 5ppm moisture with high purity nitrogen. Then introduced reactionconstituent gases to the reactor to build a gas phase condition. At thesame time heated the reactor up to the desired temperature. Charged thereactor with hydrogen gas sufficient to produce a molar ratio ofhydrogen to ethylene of 0.004 at the reaction conditions, and chargedthe reactor with 1-hexene to produce a molar ratio of 1-hexene toethylene of 0.008 (IE1) or 0.010 (IE2) at reaction conditions.Pressurized the reactor with ethylene (total pressure=220 psi) and keptthe temperature at 95° C. Once the (co)polymerizing conditions werereached, injected a feed of a slurry of Bimodal Catalyst System1 intothe reactor. Meanwhile mixed a trim solution feed with the feed ofBimodal Catalyst System1 to give a mixture thereof, which is then fedinto the reactor, wherein mixing was done at varying molar ratiosranging from 1.5 to 2.5 (Zr_(catalyst)/Zr_(trim), mol/mol) to fine tuneflow index and melt index of inventive bimodal polyethylene compositionto desired target values. Used about three bed turnovers to reachsteady-state production of the bimodal polyethylene, thereby giving theembodiment of the inventive bimodal PE composition (product) of IE1 orIE2, respectively. Collected the inventive bimodal PE composition of IE1or IE2 from the reactor's product discharge outlet and characterized itsproperties. Operating constituents and parameters are summarized belowin Table 1. Properties of the product inventive bimodal PE compositionof IE1 and IE2 are summarized later in Table 2. Densities of the LMWcomponent and the HMW component cannot be measured directly. Estimateswithin about ±0.005 g/cm³ of the densities of the LMW component and theHMW component based on kinetic models developed from historical datahave been made, but are not reported.

TABLE 1 Operating constituents/parameters for Inventive Example IE1 andIE2. Reaction Constituent/Parameter (co)polymerizing condition Reactorsingle, continuous-mode, fluidized bed Starting seedbed = granular PEresin Preloaded in reactor Reactor Purging method Anhydrous N₂ gasEthylene (“C2”) 1517 kPa partial pressure Comonomer = 1-hexene molarratio of 1-hexene/C2 = 0.008 (IE1), 0.010 (IE2) Molecular hydrogen gas(“H2”) molar ratio of H2/C2 = 0.004 Induced condensing agent 1:isopentane 6.93 mol % (IE1), 6.91 mol % (IE2) Operating temperature 95°C. Bed weight 35.4 kg (IE1), 35.5 kg (IE2) Superficial gas velocity(SGV, meters/second) 0.55 m/s

TABLE 2 properties of inventive bimodal PE composition of IE1 and IE2.Polymer Property Measured IE1 Result IE2 Result Composition Density(ASTM D792-13) 0.955 g/cm3 0.9545 g/cm3 Composition Melt Index I₂ 0.529g/10 min. 1.06 g/10 min. (190° C., 2.16 kg, ASTM D1238-04) CompositionFlow Index I₅ 2.9 g/10 min. 7.0 g/10 min. (190° C., 5.0 kg, ASTMD1238-04) Composition High-Load Flow Index I₂₁ 119 g/10 min. 287 g/10min. (190° C., 21.6 kg, ASTM D1238-04) Composition Melt Flow Ratio(I21/I2) 225 271 Composition Number-average molecular 8,381 g/mol 7,690g/mol weight (Mn) Composition Weight-average molecular 181,577 g/mol151,113 g/mol weight (Mw) Composition Molecular mass dispersity 21.6719.65 (Mw/Mn), Ð_(M) Resolved Bimodality Yes, at 4.8 LogM Yes, at 4.8LogM (GPC local minimum) LMW Polyethylene Component Conc. (wt %) 65 71HMW Polyethylene Component Conc. (wt %) 35 29 LMW Polyethylene ComponentMn (g/mol) 5,089 5,097 LMW Polyethylene Component Mw (g/mol) 13,07413,285 LMW Polyethylene Component Molecular 2.57 2.61 mass dispersity(Mw/Mn), Ð_(M) HMW Polyethylene Component Mn (g/mol) 121,000 121,500 HMWPolyethylene Component Mw (g/mol) 495,728 484,797 HMW PolyethyleneComponent Molecular 4.1 3.99 mass dispersity (Mw/Mn), Ð_(M) Long ChainBranching (LCB) Index No LCB detected No LCB detected DSC OIT at 210° C.63.6 min 60.6 min ESCR F50 >1000 hours 718 (10% Igepal at 50° C.)*Spiral Flow Length at 68.95 MPa (cm) 29.2 34.93 *Spiral Flow Length at103.4 MPa (cm) 38.74 45.7 *Spiral Flow Length at 137.9 MPa (cm) 47.6355.9

The resolved bimodalities of the inventive bimodal PE composition of IE1and IE2 are shown in FIG. 2 in comparison to that of the comparativecomposition, DMDC-1250 from The Dow Chemical Company, which comparativecomposition is monomodal.

Advantageously we discovered the inventive bimodal PE composition hasmelt properties (e.g., I₂, I₅, I₂₁, I₂₁/I₂, I₂₁/I₅) and low shrinkagevalues in flow direction or cross-flow direction that enablemanufacturing of bottle caps or closures by injection molding methods.Also, the inventive bimodal PE composition has suitable compositionproperties (e.g., density, Mw, Mn, Mw/Mn, and a resolved bimodality),suitable HMW polyethylene component properties (density, Mw, Mn, andMw/Mn), and suitable LMW polyethylene component properties (density, Mw,Mn, and Mw/Mn), that beneficially give high spiral flow index values,long time periods before observation in DSC of oxidative induction time,and long time periods before failure in ESCR.

1. A bimodal polyethylene composition comprising a lower molecularweight (LMW) polyethylene component and a higher molecular weight (HMW)polyethylene component, wherein each of the LMW and HMW polyethylenecomponents comprises ethylene-derived monomeric units and(C₃-C₂₀)alpha-olefin-derived comonomeric units; and wherein the bimodalpolyethylene composition is characterized by each of limitations (a) to(e): (a) a resolved bimodality (resolved molecular weight distribution)showing in a chromatogram of gel permeation chromatography (GPC) of thebimodal polyethylene composition, wherein the chromatogram shows a peakrepresenting the HMW polyethylene component, a peak representing the LMWpolyethylene component, and a local minimum in a range of Log(molecularweight) (“Log(MW)”) 3.5 to 5.5 between the Log(MW) peak representing theHMW polyethylene component and the Log(MW) peak representing the LMWpolyethylene component, measured according to Bimodality Test Method,described later; (b) a density from 0.950 to 0.960 g/cm³, measuredaccording to ASTM D792-13 Method B; (c) a melt index (I₂) of from 0.5 to1.5 g/10 min., measured according to ASTM D1238-13 (190° C., 2.16 kg);(d) a melt flow ratio (I₂₁/I₂) of from 150 to 300, wherein I₂ ismeasured as above and I₂₁ is flow index measured according to ASTMD1238-13 (190° C., 21.6 kg); (e) a flow index (Is) from 2.0 to 10.0 g/10min., measured according to ASTM D1238-13 (190° C., 5.0 kg); and whereinthe HMW polyethylene component of the bimodal polyethylene compositionis characterized by limitations (f) and (g): (f) a weight-averagemolecular weight (Mw) of greater than 350,000 grams per mole (g/mol), asmeasured by Gel Permeation Chromatography Method; and (g) a molecularmass dispersity, D_(M), (Mw/Mn) greater than 3.50.
 2. The bimodal PEcomposition of claim 1 further described by any one of limitations (i)to (vi): (i) a spiral flow length of from 25 to 40 centimeters (cm)measured at 68.95 megapascals (MPa), a spiral flow length from 30 to 60cm measured at 103.4 MPa, or a spiral flow length from 40 to 70 cmmeasured at 137.9 MPa according to the Spiral Flow Length Test Method;(ii) an environmental stress crack resistance (ESCR) F50 measuredaccording to ASTM D1693-15 in 10 weight percent (wt %) Igepal CO-630 inwater at 50° C. of greater than 500 hours; (iii) a shrinkage from meltto solid form of from 3.0% to 5.0% in flow direction or a shrinkage frommelt to solid form of from 0.2% to 1.5% in cross-flow direction,measured according to ASTM D-955 utilizing a 60 mm×60 mm×2 mm plaques;(iv) an oxidative induction time (OIT) of greater than 40 minutes at210° C. as measured by differential scanning calorimetry (DSC) accordingto OIT Test Method; (v) at least two of (i) to (iv); (vi) each of (i) to(iv).
 3. The bimodal PE composition of claim 1 further described by anyone of limitations (i) to (vii): (i) a molecular mass dispersity(M_(w)/M_(n)), Ð_(M) (pronounced D-stroke M), from 15 to 30, measuredaccording to Gel Permeation Chromatography (GPC) Test Method; (ii) aweight average molecular weight (M_(n)) of the LMW polyethylenecomponent from 4,000 to 6,000 g/mol and a M_(n) of the HMW polyethylenecomponent from 110,000 to 130,000 g/mol, measured according to GPC TestMethod, after deconvoluting the LMW and HMW polyethylene components ofthe bimodal PE composition according to Deconvoluting Test Method; (iii)no measurable amount of long chain branching per 1,000 carbon atoms(“LCB Index”), measured according to LCB Test Method; (iv) both (i) and(ii); (v) both (i) and (iii); (vi) both (ii) and (iii); and (vii) eachof (i) to (iii).
 4. The bimodal PE composition of claim 1 furtherdescribed by any one of limitations (i) to (iv): (i) the(C₃-C₂₀)alpha-olefin-derived comonomeric units are derived from1-butene; (ii) the (C₃-C₂₀)alpha-olefin-derived comonomeric units arederived from 1-hexene; (iii) the (C₃-C₂₀)alpha-olefin-derivedcomonomeric units are derived from 1-octene; and (iv) the(C₃-C₂₀)alpha-olefin-derived comonomeric units are derived from acombination of any two, alternatively each of 1-butene, 1-hexene, and1-octene.
 5. A bimodal polyethylene composition made by copolymerizingethylene (monomer) and at least one (C₃-C₂₀)alpha-olefin (comonomer)with a mixture of a bimodal catalyst system and a trim solution in thepresence of molecular hydrogen gas (H₂) and, optionally, an inducedcondensing agent (ICA) in one, two or more polymerization reactors under(co)polymerizing conditions; wherein prior to being mixed together thetrim solution consists essentially of a(tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconium complexand an inert liquid solvent and the bimodal catalyst system consistsessentially of an activator species, abis(2-pentamethylphenylamido)ethyl)amine zirconium complex and a(tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconiumcomplex, all disposed on a solid support; and wherein the(co)polymerizing conditions comprise a reaction temperature from 80degrees (⁰) to 110° Celsius (C.); a molar ratio of the molecularhydrogen gas to the ethylene (H2/C2 molar ratio) from 0.001 to 0.020;and a molar ratio of the comonomer (Comer) to the ethylene (Comer/C2molar ratio) from 0.005 to 0.050.
 6. A method of making the bimodalpolyethylene composition of claim 1, the method comprising contactingethylene (monomer) and at least one (C₃-C₂₀)alpha-olefin (comonomer)with a mixture of a bimodal catalyst system and a trim solution in thepresence of molecular hydrogen gas (H₂) and, optionally, an inducedcondensing agent (ICA) in one, two or more polymerization reactors under(co)polymerizing conditions, thereby making the bimodal polyethylenecomposition; wherein prior to being mixed together the trim solutionconsists essentially of a(tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconium complexand an inert liquid solvent and the bimodal catalyst system consistsessentially of an activator species, a non-metallocene ligand-Group 4metal complex and a metallocene ligand-Group 4 metal complex, alldisposed on a solid support; and wherein the (co)polymerizing conditionscomprise a reaction temperature from 80 degrees (°) to 110° Celsius(C.); a molar ratio of the molecular hydrogen gas to the ethylene (H2/C2molar ratio) from 0.001 to 0.050; and a molar ratio of the comonomer(Comer) to the ethylene (Comer/C2 molar ratio) from 0.005 to 0.10. 7.The bimodal polyethylene composition of claim 5 further described by anyone of limitations (i) to (vi): (i) wherein the bimodal catalyst systemconsists essentially of a bis(2-pentamethylphenylamido)ethyl)aminezirconium complex and a(tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconium complexin a molar ratio thereof from 1.0:1.0 to 5.0:1.0, respectively, and amethylaluminoxane species, all disposed by spray-drying onto the solidsupport; (ii) wherein the bimodal catalyst system further consistsessentially of mineral oil and the solid support is a hydrophobic fumedsilica; (iii) wherein the mixture is a suspension of the bimodalcatalyst system in mineral oil and the trim solution and wherein themixture is premade and then fed into the polymerization reactor(s); (iv)wherein the trim solution is made by dissolving(tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconiumdimethyl in the inert liquid solvent to give the trim solution; (v)wherein the polymerization reactor(s) is one fluidized bed gas phasereactor and the method is a gas phase polymerization; and (vi) each of(i) to (v).
 8. A manufactured article comprising a shaped form of thebimodal polyethylene composition of claim
 1. 9. The manufactured articleof claim 8 selected from: coatings, films, sheets, extruded articles,and injection molded articles.
 10. A bottle cap or closure comprising abase member and a skirt member, the base member defining a perimeteredge therearound, and the skirt member being in operative connection tothe perimeter edge of the base member and extending axially from theperimeter of the base member; wherein the skirt member defines an innersurface; wherein the base member being for sealing a bottle opening of abottle and the skirt member being for operatively attaching the bottlecap or closure to an exterior cap-or-closure-receiving portion of thebottle proximate the bottle opening, wherein at least one of the basemember and skirt member of the bottle cap or closure is composed of thebimodal polyethylene composition of claim 1.